// 定义三个页面
import 'package:flutter/material.dart';

class PageOne extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Container(
      color: Colors.red,
      child: Center(child: Text('Page One')),
    );
  }
}

class PageTwo extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Container(
      color: Colors.green,
      child: Center(child: Text('Page Two')),
    );
  }
}

class PageThree extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Container(
      color: Colors.blue,
      child: Center(child: Text('Page Three')),
    );
  }
}